Finite element analysis - Reinforced Concrete Deep Beams - page 236

strength and deformational properties of concrete and steel. Such laws form
the basis for the evaluation of residual forces and the elasto-plastic material
matrix [D] used in the linear solution technique. The flow chart in Figure
9.14 shows the organisation of the finite element nonlinear analysis
procedure.

9.16 Example of non-linear analysis of reinforced concrete deep beams

Dimensions and properties of example beam:
A concrete beam 480 mm deep, 1000 mm long and 100 mm thick.
Distance between centre-lines of simple supports=800 mm
Two concentrated loads at 100 mm from either side of the centre-line of the
beam were applied at top
Shear span to depth ratio=300/480=0.625
Concrete: compressive strength=25 Mpa
tensile strength=2.2 Mpa
modulus of elasticity=26 kN/mm 2
PoissonÓs ratio=0.2
Main reinforcement: Two Ï14 mild steel bars at bottom

Steel: yield stress=300 Mpa
modulus of elasticity=200 kN/mm 2
Half of the beam was idealised by 5ċ8=40 rectangular elements and 5 bar
elements as shown in Figure 9.15 a . The crack pattern arrived at after the total
load reached 70% of the ultimate load is shown in Figure 9.15b. The full curve
showing the load versus the deflection at mid-span is shown in Figure 9.15c.

f

References

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